Plug and abandonment system

ABSTRACT

A system to set a plug in a wellbore includes a tubular member and a plug coupled to the tubular member. The plug is configured to seal a wellbore based, at least in part, on a shape change of the plug.

BACKGROUND

The present disclosure relates generally to wellbore operations and, more particularly, to a plug and abandonment system.

Open hole plug and abandonment cement plugs require a reliable fundament to achieve successful separation of fluids. Conventional products may only separate the fluids and may not be able to hold any differential pressure that can occur due to losses and weight changes. For horizontal wells, the adequacy of conventional products is particularly questionable.

Well integrity has become more and more highlighted in the industry, and a reliable solution to overcome the above issue is needed. There is a need to have a reliable base for plug and abandonments in open hole and cased hole that will be able to hold differential pressure and avoid losses to the formation, in addition to being able to separate fluids. And, in cases of nearby wells, there is a need for ensuring isolation of water breakthrough because of nearby production.

SUMMARY

The present disclosure relates generally to wellbore operations and, more particularly, to a plug and abandonment system.

In one aspect, a system to set a plug in a wellbore is disclosed. The system may include a tubular member and a plug coupled to the tubular member. The plug may be configured to seal a wellbore based, at least in part, on a shape change of the plug.

In another aspect, a method of setting a plug within a wellbore is disclosed. The method may include providing a plug coupled to a tubular member. The plug may be configured to seal a wellbore based, at least in part, on a shape change of the plug. The method may also include positioning the plug within the wellbore and inducing the shape change to seal the wellbore.

In yet another aspect, a plug to seal a wellbore is disclosed. The plug may include a tubular member, a layer of compressible material disposed about a portion of the tubular member, and a moveable member adjacent to the layer of compressible material to axially compress the layer of compressible material. The layer of compressible material may expand radially when compressed axially.

Accordingly, certain embodiments according to the present disclosure may ensure well integrity and may provide a reliable base for plug and abandonments in open hole and cased hole that will in addition to separating the fluids, be able to hold differential pressure and avoid losses to the formation. Certain embodiments may ensure isolation of water breakthrough because of production from nearby wells. Certain embodiments also may have the swellable feature of closing gaps that may tend to form over time due to formation changes.

The features and advantages of the present disclosure will be readily apparent to those skilled in the art. While numerous changes may be made by those skilled in the art, such changes are within the spirit of the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

Some specific exemplary embodiments of the disclosure may be understood by referring, in part, to the following description and the accompanying drawings.

FIG. 1 illustrates a plug and abandonment system, in accordance with certain embodiments of the present disclosure.

FIGS. 2A and 2B respectively illustrate a plug of the plug and abandonment system in inactivated and activated states, in accordance with certain embodiments of the present disclosure.

FIG. 3 illustrates the plug and abandonment system in an activated state, in accordance with certain embodiments of the present disclosure.

FIG. 4 illustrates the plug and abandonment system at the cementing stage, in accordance with certain embodiments of the present disclosure.

FIGS. 5A and 5B illustrate one exemplary disconnect tool, in accordance with certain embodiments of the present disclosure.

While embodiments of this disclosure have been depicted and described and are defined by reference to exemplary embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and not exhaustive of the scope of the disclosure.

DETAILED DESCRIPTION

The present disclosure relates generally to wellbore operations and, more particularly, to a plug and abandonment system.

Illustrative embodiments of the present disclosure are described in detail herein. In the interest of clarity, not all features of an actual implementation may be described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation specific decisions must be made to achieve the specific implementation goals, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of the present disclosure.

To facilitate a better understanding of the present disclosure, the following examples of certain embodiments are given. In no way should the following examples be read to limit, or define, the scope of the disclosure. Embodiments of the present disclosure may be applicable to horizontal, vertical, deviated, or otherwise nonlinear wellbores in any type of subterranean formation. Embodiments may be applicable to injection wells as well as production wells, including hydrocarbon wells.

Certain embodiments according to the present disclosure may provide a plug and abandonment system that may provide for plug placement, activation, and release. The plug and abandonment system may allow for fluid bypass and circulation in an inactivated state, and may be used to create a false well bottom in an activated state. Further, the plug and abandonment system may aid in setting balanced and competent cement plugs during remedial and primary cementing operations and may allow for successful first-attempt plug setting.

FIG. 1 illustrates a plug and abandonment system 100 in accordance with certain embodiments of the present disclosure. In the non-limiting example depicted, the plug and abandonment system 100 includes a tubular member 105, which may include or be coupled to a workstring. The workstring may include a series of coupled tubular members (not shown) coupled in any conventional manner. By way of example without limitation, adjacent tubular members may be threadedly connected at corresponding end portions. A continuous bore may be defined by the tubular members and the tubular member 105, and may extend for the length of the workstring. As depicted, the plug and abandonment system 100 may be lowered into a borehole 120, which may be an open borehole or a cased borehole. The tubular member 105 may be coupled to a disconnect and activation tool 110. In certain embodiments, the tubular member 105 may comprise a drill pipe.

A plug 115 may be coupled to the tubular member 105 via the disconnect and activation tool 110. The plug 115 may be lowered to any desired position within the borehole 120, including an off-bottom position. The borehole 120 may contain fluid disposed about the plug and abandonment system 100. As shown in FIG. 1, with the plug 115 in an inactivated state and not sealing the borehole 120, an annulus 121 may be defined between the plug 115 and a surface of the borehole 120. In that inactivated state, the plug and abandonment system 100 may allow for fluid bypass and circulation.

The plug 115 may be formed to have any suitable dimensions in the inactivated state to fit within various boreholes, depending on the implementation. However, once activated, the plug 115 may expand radially to fill the annulus 121. In particular, the plug 115 may be capable of being compressed longitudinally (i.e., generally along an axis of the plug 115) to change shape and expand radially until its outer surface substantially sealingly contacts the surface of the borehole 120. It should be recognized that the plug 115 may be made of different materials, shapes, and sizes.

FIGS. 2A and 2B respectively show an exemplary plug 115 of the plug and abandonment system 100 in an inactivated state and in an activated state, in accordance with certain embodiments of the present disclosure. The plug 115 may include a tubular member 106, which may be a base pipe in certain embodiments. The plug 115 may include one or more layers 116. For example without limitation, an inner layer 116A may surround or partially surround the tubular member 106. A sleeve 116B may surround or partially surround the inner layer 116A. Once the plug 115 has been activated, the sleeve 116B may facilitate the maintenance of the one or more layers 116 in the compressed condition. An outer layer 116C may surround or partially surround the sleeve 116B. The inner layer 116A and outer layer 116C may include an elastomer material in certain embodiments. The sleeve 116B may include steel in certain embodiments. In other various embodiments, one or more of the inner layer 116A, sleeve 116B, and outer layer 116C may include any other suitable material that allows for a shape change of the plug 115 as disclosed herein. And in alternative embodiments, alternatives to the sleeve 116B (e.g., a squirrel cage-like structure, or any other suitable structure) may be used to facilitate the shape change of the plug 115.

The plug 115 may include a ring 119A disposed about the tubular member 106. A base 119B may be disposed generally opposite to the ring 119A, relative to the one or more layers 116, at a distal portion of the plug 115. The ring 119A may slidingly engage the tubular member 106 so that, with a suitable force applied to the ring 119A, the ring 119A may slide along the tubular member 106 and compress the one or more layers 116 against the base 119B so that the one or more layers 116 expand radially, as illustrated in FIG. 2B. The ring 119A and the base 119B may include any suitable material and may have any suitable form that facilitates compression of the one or more layers 116 when a suitable force is applied to the ring 119A.

FIG. 3 illustrates the plug and abandonment system 100 in the activated state, in accordance with certain embodiments of the present disclosure. As depicted, the shape change of the plug 115 accordingly may provide a hydraulic seal against the inner diameter of the borehole 120. In this manner, the plug 115 may be set on-demand.

The plug 115 may be fabricated in any suitable manner so that it can be coupled to the disconnect and activation tool 110. The disconnect and activation tool 110 may include an activation feature 111. The activation feature 111 may include any suitable means for conveying a suitable force to compress the plug 115. In certain embodiments, the activation feature 111 may allow for a pressure inside the tubular 105 to be transferred, directly or indirectly, to compress the plug 115. In certain embodiments, the pressure may be transferred, directly or indirectly, to the ring 119A of the plug 115 in the non-limiting example illustrated in FIGS. 2A and 2B. In certain embodiments, the activation feature 111 may include an activation ball or dart that may be dropped within the tubular member 105 to the activation tool 110. As such, the activation feature 111 may be a surface-released, ball-operated or dart-operated, activation tool. When the activation ball or dart lands in the disconnect and activation tool 110, a pressure inside the tubular 105 may be transferred, directly or indirectly, to the compress plug 115.

With the plug 115 in the activated state as depicted in FIG. 3, the plug 115 may be disconnected from the tubular member 105. FIG. 4 illustrates the plug and abandonment system 100 at a cementing stage with the plug 115 disconnected from the tubular member 105, in accordance with certain embodiments of the present disclosure. With the plug 115 in the activated state, the tubular member 105 may be pulled a suitable distance away from the plug 115. Cement 130 may be conveyed via the tubular member 105 to a portion of the wellbore above the plug 115 after the separation of the tubular member 105 from the plug 115 has occurred. Centralizers (not shown) may be necessary to help hold the tubular member 105 tubing in place at this stage.

In various embodiments, the disconnect and activation tool 110 may be one of many types; the particular type may depend on well path, temperature, size, price, etc. Any suitable drop-off tool may be used. The disconnect and activation tool 110 may be a mechanically operated release device made of steel or composite, for example. By way of non-limiting example, the disconnect and activation tool 110 may be ball-operated or dart-operated. A ball or a dart may be dropped into the work string and displaced to the disconnect and activation tool 110. With suitable pressure applied from the behind to displace the ball or dart, the disconnect and activation tool 110 may be activated to disconnect the plug from the tubular 105. In certain embodiments, the disconnect and activation tool 110 may be connected to the plug 115 with a mechanical locking mechanism. In various embodiments, the disconnect and activation tool 110 may be adapted to either be retrieved to the surface with the tubular member 105 or to remain with the plug 115 downhole. Certain non-limiting details of exemplary tool structure and operation are provided in U.S. Pat. No. 6,772,835, which is hereby incorporated by reference in its entirety for all purposes.

By way of example without limitation, FIGS. 5A and 5B illustrate one disconnect and activation tool 110, in accordance with certain embodiments of the present disclosure. FIG. 5A shows the disconnect and activation tool 110 in the connected state; and FIG. 5B shows the disconnect and activation tool 110 in the disconnected state. The disconnect and activation tool 110 comprises an upper body member 124 that may be coupled to the tubular member 105 and a lower body member 126 that may be coupled to the plug 115. The two body members are quick-releasably coupled together, and the upper member 124 defines a seat for receiving a flow prevention tool. The flow prevention tool may be a releasing dart or a ball. The flow prevention tool may be a ball valve as disclosed in U.S. Pat. No. 7,472,752, which is hereby incorporated by reference in its entirety for all purposes. The seat has a greater diameter than the ball valve so as to allow the latter ball valve to pass through the disconnect 110.

In certain embodiments, the plug 115 may include a swellable material. The swellable material may be able to close gaps that tend to form. For example, gaps may form over time due to formation changes that can occur due to faulting, depletion shrinkage, or stresses. In certain embodiments, the swellable material may expand to increase the sealing contact between the plug 115 and the borehole 120. In general, the plug 115 generally should remain dormant until the activation agent is introduced to the swellable material. The term “swellable” is used herein to indicate an increase in volume of a material. Typically, this increase in volume is due to incorporation of molecular components of a fluid into the swellable material itself, but other swelling mechanisms or techniques may be used, if desired. The swellable material may swell when contacted by an activating agent, such as an inorganic or organic fluid. In one embodiment, a swellable material may be a material that swells upon contact with and/or absorption of a hydrocarbon, such as oil. In another embodiment, a swellable material may be a material that swells upon contact with and/or absorption of an aqueous fluid.

Suitable swellable materials include, but are not limited, to those disclosed in U.S. Pat. Nos. 3,385,367; 7,059,415; and 7,143,832; the entire disclosures of which are incorporated by reference. Some exemplary swellable materials may include, but are not limited to, elastic polymers, such as EPDM rubber, styrene butadiene, natural rubber, ethylene propylene monomer rubber, ethylene-propylene-copolymer rubber, ethylene propylene diene monomer rubber, ethylene-propylene-diene terpolymer rubber, ethylene vinyl acetate rubber, hydrogenized acrylonitrile butadiene rubber, acrylonitrile butadiene rubber, isoprene rubber, butyl rubber, halogenated butyl rubber, brominated butyl rubber, chlorinated butyl rubber, chlorinated polyethylene, chloroprene rubber and polynorbornene. In one embodiment, the rubber of the swellable material may also have other materials dissolved in or in mechanical mixture therewith, such as fibers of cellulose. Additional options may be rubber in mechanical mixture with polyvinyl chloride, methyl methacrylate, acrylonitrile, ethylacetate or other polymers that expand in contact with oil. Other swellable materials that behave in a similar fashion with respect to hydrocarbon fluids or aqueous fluids also may be suitable. Those of ordinary skill in the art, with the benefit of this disclosure, will be able to select an appropriate swellable material for use in the present invention based on a variety of factors, including the desired swelling characteristics of the swellable material and the environmental conditions in which it is to be deployed.

Delay systems may be used to delay the swelling activation in certain embodiments. For example, swellable material elements may be encapsulated so that they generally do not swell until after a delay period after exposure to hydrocarbon and/or water. The hydrocarbon is absorbed into the swellable material such that the volume of the swellable material increases creating an expansion of the swellable material.

Accordingly, certain embodiments according to the present disclosure may enable the placement of a competent plug downhole. Thus, certain embodiments may ensure well integrity and may provide reliable plug and abandonment in open hole and cased hole implementations. Certain embodiments may provide zonal isolation on demand, being able to hold differential pressure and avoid losses to the formation. Certain embodiments may ensure isolation of water breakthrough because of production from nearby wells. Certain embodiments also may have the swellable feature of closing gaps that may tend to form over time due to formation changes. Certain embodiments may avoid the problems of conventional plugging approaches that are vulnerable to contamination and disturbance during initial setting. With certain embodiments, there is no need for a separate physical barrier between a cement plug and the fluid below the plug, as is needed in conventional operations to prevent the introduction of cement slurry into in the fluid.

Even though the figures depict embodiments of the present disclosure in a particular orientation, it should be understood by those skilled in the art that embodiments of the present disclosure are well suited for use in a variety of orientations. Accordingly, it should be understood by those skilled in the art that the use of directional terms such as above, below, upper, lower, upward, downward and the like are used in relation to the illustrative embodiments as they are depicted in the figures, the upward direction being toward the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure.

Therefore, the present disclosure is well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the present disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered or modified and all such variations are considered within the scope and spirit of the present disclosure. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. The indefinite articles “a” or “an,” as used in the claims, are each defined herein to mean one or more than one of the element that the article introduces. 

What is claimed is:
 1. A system for setting a plug in a wellbore, the system comprising: a tubular member; and a plug coupled to the tubular member, wherein the plug is configured to seal a wellbore based, at least in part, on a shape change of the plug.
 2. The system of claim 1, wherein the plug is selectively decouplable from the tubular member.
 3. The system of claim 2, wherein the plug is selectively decouplable from the tubular member based, at least in part, on a pressure applied via the tubular member.
 4. The system of claim 1, wherein the shape change of the plug is based, at least in part, on a pressure applied via the tubular member.
 5. The system of claim 1, wherein the plug comprises an axis and is compressible along the axis.
 6. The system of claim 1, wherein the shape change of the plug comprises a radial expansion.
 7. The system of claim 1, wherein the plug comprises a plurality of layers.
 8. The system of claim 7, wherein one or more of the plurality of layers is configured to maintain the plug in an activated state.
 9. The system of claim 1, wherein the plug comprises a swellable material.
 10. The plug setting system of claim 1, wherein the tubular member is part of a workstring that allows positioning of the plug within the wellbore prior to sealing the wellbore.
 11. A method of setting a plug within a wellbore, the method comprising: providing a plug coupled to a tubular member, wherein the plug is configured to seal a wellbore based, at least in part, on a shape change of the plug; positioning the plug within the wellbore; and inducing the shape change to seal the wellbore.
 12. The method of setting the plug within the wellbore of claim 11, further comprising: decoupling the tubular member from the plug.
 13. The method of setting the plug within the wellbore of claim 12, wherein the step of decoupling the tubular member from the plug is based, at least in part, on a pressure applied via the tubular member.
 14. The method of setting the plug within the wellbore of claim 11, wherein the step of inducing the shape change to seal the wellbore comprises: compressing the plug along an axis of the plug.
 15. The method of setting the plug within the wellbore of claim 11, wherein the shape change of the plug comprises a radial expansion.
 16. A plug to seal a wellbore, the plug comprising: a tubular member; a layer of compressible material disposed about a portion of the tubular member; and a moveable member adjacent to the layer of compressible material to axially compress the layer of compressible material; wherein the layer of compressible material expands radially when compressed axially.
 17. The plug to seal the wellbore of claim 16, wherein the moveable member compresses the layer of compressible material based, at least in part, on a pressure applied via the tubular member.
 18. The plug to seal the wellbore of claim 16, further comprising: a base disposed at a distal end of the layer of compressible material.
 19. The plug to seal the wellbore of claim 16, wherein the layer of compressible material is selectively decouplable from a workstring.
 20. The plug to seal the wellbore of claim, further comprising: a sleeve configured to maintain the layer of compressible material in a compressed state. 